feat: pass alarm style through crontab manager and GraphQL API

- crontab_manager.get_alarms now parses --style from the cron command
  (defaults to 'blink' for legacy entries without --style)
- GraphQL Alarm type gains a 'style' field
- setAlarm accepts a 'style' arg (default 'simple') and validates it
  against the styles registry; unknown styles raise a GraphQL error
- _default_command embeds --style <name> into the cron command
- startRinging accepts 'style' (default 'simple') and passes --style to
  the spawned wecker.py

The crontab remains the single source of truth; the style simply rides
in the cron command alongside --music-file.

api/schema.py

@@ -1,6 +1,7 @@
 import strawberry
 from typing import List, Optional
 import os
+import shlex
 import sys
 import time
 import subprocess
@@ -8,6 +9,7 @@ import signal
 from pathlib import Path
 from api.crontab_manager import CrontabManager
 from common import PID_FILE
+from styles import get_style
 
 
 def get_manager():
@@ -42,7 +44,7 @@ def _project_root() -> Path:
     return start.parent.parent
 
 
-def _default_command() -> str:
+def _default_command(style: str) -> str:
     """Return the default shell command to run wecker.py from crontab."""
     project_root = _project_root()
     python_exec = sys.executable
@@ -50,18 +52,18 @@ def _default_command() -> str:
     return (
         f"cd {project_root} && "
         f"XDG_RUNTIME_DIR={runtime_dir} SDL_AUDIODRIVER=pulse "
-        f"{python_exec} wecker.py >> wecker.log 2>&1"
+        f"{python_exec} wecker.py --style {shlex.quote(style)} >> wecker.log 2>&1"
     )
 
 
-def _start_wecker_process() -> subprocess.Popen:
+def _start_wecker_process(style: str) -> subprocess.Popen:
     """Start wecker.py without invoking a shell."""
     project_root = _project_root()
     env = os.environ.copy()
     env.setdefault("SDL_AUDIODRIVER", "pulse")
     env.setdefault("XDG_RUNTIME_DIR", f"/run/user/{os.getuid()}")
     return subprocess.Popen(
-        [sys.executable, str(project_root / "wecker.py")],
+        [sys.executable, str(project_root / "wecker.py"), "--style", style],
         cwd=project_root,
         stdout=subprocess.DEVNULL,
         stderr=subprocess.DEVNULL,
@@ -75,6 +77,7 @@ class Alarm:
     id: str
     cron_expression: str
     is_enabled: bool
+    style: str
 
 
 def _alarm_from_dict(data: dict) -> Alarm:
@@ -83,6 +86,7 @@ def _alarm_from_dict(data: dict) -> Alarm:
         id=data["id"],
         cron_expression=data["cron_expression"],
         is_enabled=data["is_enabled"],
+        style=data["style"],
     )
 
 
@@ -118,8 +122,10 @@ class Mutation:
         cron_expression: str,
         is_enabled: bool = True,
         id: Optional[str] = None,
+        style: str = "simple",
     ) -> Alarm:
-        command = _default_command()
+        get_style(style)  # validate; raises ValueError on unknown style
+        command = _default_command(style)
 
         manager = get_manager()
         new_id = manager.set_alarm(
@@ -132,6 +138,7 @@ class Mutation:
             id=new_id,
             cron_expression=cron_expression,
             is_enabled=is_enabled,
+            style=style,
         )
 
     @strawberry.field
@@ -146,12 +153,13 @@ class Mutation:
         return False
 
     @strawberry.field
-    def start_ringing(self) -> bool:
+    def start_ringing(self, style: str = "simple") -> bool:
         """Start the wecker alarm if it is not already ringing.
         Returns True if started, False if already ringing."""
         if is_wecker_ringing():
             return False
-        _start_wecker_process()
+        get_style(style)  # validate; raises ValueError on unknown style
+        _start_wecker_process(style)
         return True
 
     @strawberry.field